I know what colloquial means, but apes cannot be colloquially referred to as monkeys. They are to far removed. You are confusing something being colloquial with something being a common misconception, that many people do not understand taxonomy at a middle school level does not make it a correct statement. Also, colloquial generally refers to how “proper” the language is being spoken (including the usage of slang and stuff like that), and not the factual correctness of it.